There is increasing interest in television broadcasting to portable devices. However the majority of film and television productions are intended for large displays; and the move to high definition television has encouraged the use of wide camera angles where the viewer tracks the action with his eyes rather than the camera tracking the action by pan, tilt, crab and zoom.
Where the display device is small it is usually necessary to limit the field of view to the most important part of the scene and, even then, key features of the action may be too small for the viewer to resolve them. This has led to a need to adapt video material for small displays. Such adaptation is possible by a human editor adjusting the settings of a digital video processor, but this is expensive and unsuitable for live production. There is therefore great interest in automating the processing of video material to make it more suitable for small-screen displays.